Electrical coil



H. P. ACLAUSEN ELECTRICAL COIL sept. 13, 1927. 1,642,488

Filed July 2, 1923 2 Sheets-Sheet l Sept' 1 3, 1

H. P. cLAUsEN ELECTRICAL COIL Filed July 2, 1923 V12 Sheets-Sheet 2 (KTQ. 47 4/ )l a w1 45 f 43 50 i :l 5455 57 l I @I lil Patented sept.13.1927.

UNITED STATES PATENT .OFFICE HENRY P. CLAUSEN, F MAMARONECK, NEW YORK,kASSIGrNOR TO WESTERN ELEC- TRIC COMPANY, INCORPORATED, OF NEW YORK, N.Y., .A CORPORATION OF NEW YORK.

ELECTRICAL COIL.

This invention relates to an electrical coil.

It is found that in loop antennae and in tuning inductances andtransformers for receiving or transmitting radio frequency currents,there is a certain optimum number of turns at .which energy of a givenfrequency or Wave length will be most efficiently transmitted. Moreover,experiment shows that in loop antennae having the proper number of turnsfor a given wave length, the reception factor will be a maximum for thiswave length, if there are no dead end turns.

It is an object of this invention, therefore, to provide an electricalcoil the `effective turns of which are' variable and in which end turneffects are nullified. Another object is to provide an, electrical coilhaving an intermediate tap whereby its effective turns may be varied byinfinitesimal amounts. A further object is to providea variable coiladapted for use as a loop antenna in which the effective turns may bevaried, the effect of end turns nullied, and the unwound portions ofthecoil may be automatically rewound.

Thus, the electrical coil may 'comprise a. bare conductor arranged toform one or more helical sections. Contact members are provided betweensections of 'such character as to make continuous electrical connectionwith the bare conductor during thel process of adjustment. In order tonullify the effect of dead end turns, conducting cylinders are providedupon which the ineffective turns of the coil are rewound. The-samedevice may serve both as a variable contact member and for annulling endturn effects, or separate' devices may be provided to perform theseseparate functions.

1 When used as a loop antenna, this electrical coil is vpreferablyprovided with means for automatically winding or unwinding the coilsections and for maintaining the coil in its adjusted position.

In 4the drawings Figs. 1 and 2 are top plan and end elevationrespectively of an inductance coil having a variable intermediatetap.

Figs. 3 and 4 are top plan and end elevations respectively of aninductance coil havin a plurality of variable intermediate taps.

'igg. 5 is a top plan of an inductance coil havin the winding thereof ontworotatable cylin' ers.

Fig. 6 is a sectional view on line 6- -6` of Fig.

Figs. 7 and 8 are front and side elevations respectively of a loopantenna whose effective turns are variable.

Fig: 9 shows diagrammatically a radio `receivingsystem employinginductance coils of the preceding figures.

The inductance coil of Figs. 1 and 2 has two sections the effectiveturns of which may be varied with respect to each other.

This inductance coil comprises a bare conductor 10 wound into a helixand supported by a cylinder 11l of insulating material perlpherallygrooved for the reception of the conductor. The cylinder 11v isrotatably mounted in brackets 12 and 13 projecting from a base 14. Theends of conductor 10 are electrically connected to the supportingbrackets 12 and 13 provided with terminals 15 and 16 to which circuitleads may be con.- nected.

The variable intermediate tap is formed by looping the conductor 10 overa peripherally grooved nut 17 carried by and mov. ablealong a screwshaft 18 fastened in supporting brackets 19 and 20., The c onductor 10engaging nut 17 is electrically connected i to bracket 19 providedv witha terminal 21,

to which a. circuit lead may be connected.

The effective turns of the twol sections of the inductance coil may bevaried by means.

of a knurled knob 22 fixed to the end of one of the mount-ing` spindlesof cylinder 11. The portion of'conductor 10 passing from 'cylinder 11over the'nut 17 and back to the cylinder is taut, so that whenever thecylinder is-rotated the nut is caused to rotate and move along the screwshaft 18.

This coil structure may. be employed as a potentiometer.

The inductance coil of Figs. 3 and 4, similar to that shown in Figs. 1and 2, is provided with a second Variableintermediale tap.

This second variable .intermediate tap is formed by looping theconductor 10 over a peripherally grooved nut 25 carried by and sleeve 28has fixed thereto a knurledy knob 29 by which it may be rotated. Thediameter of traveling nut is one half that of cylinder 11 and the pitchof the threads of screw shaft 26 is one half that of the grooves incylinder 1l, so that the nut 25 will travel in step with thecorrespondingloop in the conductor '10.

The conductor loop engaging traveling nut 25 -is electrically connectedto terminal 15. The end of conductor 10 adjacent the supporting bracket12 is connected toa slip ring which is engaged by a contact brush 31mounted upon and insulated -from the a bracket 12. The contact brush 3lmay take the form of a flat spring to one end of which a circuit leadmay be connected.

By turning knob 22 the cylinder 11 is rotated thereby causing thetraveling nuts 17 and 25 to move along their respect-ive screw shafts.Thus the effective turns of the sections of the inductance coil arevaried.

By turning knob, t-he arm 27 and the screw shaft 26 are rotated, so asto vary relatively the effective vturns of the middle and the y cuitsthe ineffective turns.

The two cylinders 41 and 42 are rotatably supported by shafts 4l and 42fixed in end plates 43 and 44 which may be supported by a suitable base(not shown).

One end of conductor is connected to a slip ring 45 fastened to cylinder41. A contact brush 46 mounted upon and insulated from the end plate 44engages ring 45. A circuit lead may be connected to the free end of thecontact brush.

The other end of conductor 40 is connected to a slip ring 47 on cylinder42, and a cont-act brush 48 engages the ring 47. The contact brush 48 issupported by and insulated from the end plate 43.

The conductor 40 in being wound from one cylinder to 'the other passesbetween y and f partially around elongated guiding rollers 49 and 50supported by rods fastened in the end plates 43 and 44.

The means for varying the effective turns of the inductance coilcomprises two meshing gears 51 and 52 respectively mounted upon androtatable' with bearing sleeves 41* and 42a of 'the respectivecylinders. The

-gear 52 meshes with a pinion 53 on a short shaft 54 journalled in acover plate 55 fastened to the fixed shafts 41: and 42. By

turning knurled knob 56 secured to shaft '54, the two cylinders arerotated in opposite directions whereby t-he number of turns on onecylinder is increased while the number on the other is decreased.

If the cylinder 42 be made of insulating instead of conducting material,the induc- 'tance coil then becomes one havin two sections whoseeffective turns may Ihe varied relatively. The intermediate top of sucha two section inductance coil is formed by the guiding rollers 49 and 50which may be electrically connected to a terminal 57 mounted upon endplate 44.

The cores of the cylinders shown in any of the Figs. 1 to 6 may ifdesired be of Ina-gnet-ic material.

Figs. 7 and 8 show a loop antenna formed of two coils 65 and 66 eachcomprising a plurality of turns of bare conductor. Each coil is wound ona frame 67 rotatably mounted on a shaft fastened in the upper end of astandard 68 rising from a base 69.

One end of coil 65 is connected to a terminal 70 and the other end to a.metallic cylinder 71 fixed to a shaft journalled in the standard 68. v

The other coil 66 has the ends thereof connected respectively toterminal 72 and metallic cylinder 73. Cylinder 73 is fixed tothe shaftupon which cylinder 71 is mounted.

The two cylinders 71 and 73 are electrically connected to aterminal 74.

The shaft' 71 carrying cylinders 71 and 73 has fastened thereto a crank75 by which the 'cylinders may be rotated to unwind the conductors fromcoils '65 and 66 and wind the same onto the respective cylinders.

Spiral springs 76 and 77 associated respectively with the coils 65 and66 have one end thereof fastened to the shaft supporting the coil framesand the other ends connected to the respective coil frames.

These spiral springs tend normally to wind the conductors onto therespective coil frames and to turn the supporting coil frames inopposite directions.

As 'the crank 75 is turned to unwind the conductors from the coils, theconductors are unwound against the tension of the spiral springs.

A spring pressed brake 78 mounted on the f lll() Fig- 9 is a radioreceiving system utilizlao rent supplyl battery and filament of tube .Yparallel with the `100. 110 represents any ing` the variable inductancecoils for enab 'ng the various adjustments necessary for reception ofany desired signal to be made Without the use of variable condensers.

This system comprises an antenna connected to ground coil 92 and theprimary 93 of transformer 94. The loading coil 92 is preferably similarto the coil illustrated in Figs. 5 and 6 in which the active portion ofthe coil is Wound on insulating cylinder 41 and the dead end turns areshort-circuited upon a conducting cylinder 42. Transformer 94 maycomprise two coils each like that shown in Figs. 5 and 6 placed with theactive portions of their windings in mutual inductive relation and theinactive portions short circuited by the conducting cylinders. Tuning bymeans of this transformer may be accomplished either by adjusting thenumber of turns on the primary 93 or by adjusting the number of theturns on the secondary 95 or by both adjustments. v

The secondary Winding of transformer 94 is connected to the inputcircuit of a Well known form of three-element electron discharge device96. A xed condenser 97 is shunted across the secondary Winding 95 of thetransformer 94 for the purpose of introducing a stabilizing capacity inthe circuit. A potentiometer 99, which is preferably similar to thedevice shown in Fig.

1, has the terminals of its Winding connected across the terminals ofbattery 100 and in lilament of tube 96. The midpoint of potentiometer 99is preferably connected to one terminal of the secondary' winding oftransformer 94. The opposite terminal of this winding is connected tothe grid 96. The potentiometer 99 enables the polarizing potential onthe grid of tube 96 to be adjusted.

A second lthree-element 'vacuum tube 101 has an input circuit connectedto its grid and filament comprising the secondary of the transformer 104similar to transformer 94 and a grid leak resistance 106 in shunt aboutThe primary winding .103 of transformer 104 is connected in series witha plate cur- 108 to the plate and filament of tube 96. The lament oftube 101 is preferably connected in parallel with the filament of tube96 and is conseiuently supplied with heating currentfrom attery form ofdevice responsive to signal current, for example, a telephone receiverconnected tothe plate 101 in series with a por :it 91 4through aloadingv vembodiments of this a blocking condenser 107.`

tion of the battery 108. 'Resistances 98 and 102 are placed in thecircuit in series with filaments of tubes 96 and 101 respectively forthe purpose of enabling the currents by which the filaments are heatedto,be adjusted. v

rlhe form of .coil antenna shown in Figs. 7 and 8 may be substituted forthe antenna of Fig. 9. This substitution may be effected by connectingthe terminals 70 and 72 of the loop of Figs. 7 and 8 to the points 112and 113 of the circuit in Fig.'9 and by disconnecting transformer 94therefrom. The antenna 90, coil 92 and transformer 94 are therebydisassociated from the circuit. Tuning with this arrangement may beeffected by varying the number of turns on the coils 65 and 66 of theloop antenna. denser 97 acts also in this circuit as a sta- The couplingbetween and detector tube 101 varying the turns of bilizing capacity.the amplifier tube 96 may be adjusted by transformer 104. v

It is to be understood that the specific invention herein shown anddescribed are merely illustrative of the novel principles involved andare ,in no Wise intended to restrict their application. The only limitsthat are intended to be fixed The conv upon the scope of this inventionwill appear lfrom the following claims.

What is claimed is:

rotatable insulating cylinder having a helically grooved periphery, awinding of bare conductor in the grooves, a circular metallic elementcarrying. at least a portion of one turn of said conductor, means forrotating said cylinder,` and means associated with said element forcausing it to move with the loop of the conductor and to maintaincontinuous electrical connection therewith.

2. An inductance coil comprising a rotatable insulating cylinder havinga helically grooved surface, a winding of bare conductor in the grooves,means for rotating said cylinder, and means for making an electricalcontact at an intermediate point of said winding, said means comprisinga conducting lead-screw having a circular metallic nut mounted thereon,a turn of the coil being looped over said nut, and the pitch of saidscrew being proportioned to advance the nut equally with the windingloop as the cylinder is rotated.

In witness whereof, I hereunto -subscribe my name this 28th day of June,A. D. 1923.

HENRY P. CLAUSEN.

1. A variable electr'cal coil comprising .a v

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